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When to Plant Hyssop in Flagler County, FL

Flagler County, Florida Zone 9b May

Top priorities for Flagler County, Florida gardeners in May

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost February 5
Avg. first frost December 17
Soil temp (4") 77°F
Watering Moderate
Pest pressure High
Daylight 13.5 hrs
  1. Collect hyssop at their peak

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

A few tasks this May that'll pay off in June
  • First harvests: hyssop

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Hyssop is a semi-evergreen perennial herb with intense blue flower spikes that attract bees and butterflies. It has a minty, slightly bitter flavor used in liqueurs and teas.

Flagler County, Florida is in USDA Zone 9b. The average last spring frost is February 5 and the first fall frost is December 17, giving you a growing season of approximately 315 days.

At an elevation of 134 feet, Flagler County receives approximately 54.2 inches of rainfall annually with predominantly sand soil. Summer highs average 99°F, so Hyssop may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Hyssop will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Hyssop root diseases.

Flagler County, FL (Zone 9b) Year-round
315 days
Last Spring Frost February 5
315 growing days
First Fall Frost December 17

Flagler County Soil Profile

Soil Type

Sand

Soil pH

5.1-5.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (180 days to spare)
Transplant: Jan 29 🍅 Harvest: Apr 9 – Jun 11
Recommended (50%) ✓ Fits season (175 days to spare)
Transplant: Feb 12 🍅 Harvest: Apr 23 – Jun 25
Safe Start (90%) ✓ Fits season (161 days to spare)
Transplant: Mar 7 🍅 Harvest: May 16 – Jul 18

Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.

Soil Compatibility in Flagler County

How your county's soil matches Hyssop's growing requirements.

Soil pH

Your soil pH (5.1–5.7) is more acidic than Hyssop prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

Sandy soil in Flagler County warms quickly in spring but drains fast. Hyssop will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for Hyssop.

Organic Matter

Organic matter is low (1.6%). Add 2-3 inches of compost before planting Hyssop.

How to Plant Hyssop

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Hyssop

5
successive plantings in your 315-day season

Sow every 8 weeks. Last sowing by Sep 18 to harvest before frost.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.7″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Hyssop

Hyssop needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Hyssop Needs Rainfall You Supplement Action
Jan 2.7" 0" ❄️ Dormant
Feb 2.2" 2.5" 0" ✅ Rainfall sufficient
Mar 2.2" 3" 0" ✅ Rainfall sufficient
Apr 2.2" 2.2" 0" ✅ Rainfall sufficient
May 2.2" 3.7" 0" ✅ Rainfall sufficient
Jun 2.2" 8.8" 0" ✅ Rainfall sufficient
Jul 2.2" 7.7" 0" ✅ Rainfall sufficient
Aug 2.2" 7.4" 0" ✅ Rainfall sufficient
Sep 2.2" 6.9" 0" ✅ Rainfall sufficient
Oct 2.2" 4.7" 0" ✅ Rainfall sufficient
Nov 2.2" 2" 0.2" 💧 Light watering
Dec 2.2" 2.5" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Flagler County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Hyssop Heat Requirements (GDD)

What are Growing Degree Days (GDD)?

Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.

Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.

Hyssop needs ~1,940 GDD — county provides 7,663 GDD Excellent fit

Hyssop Planting Timeline — Flagler County, FL

Hyssop Planting Calendar

Activity When Date Range
Transplant Outdoors February 12 Feb 12 – Feb 26
Harvest April 23 Apr 23 – Jun 25

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February Transplant Outdoors
March
April Harvest
May Harvest
June Harvest
July
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9b

📆 Growing Season

315 days in Flagler County

Growing Tips for Hyssop in Flagler County

Direct sow Hyssop outdoors after February 05 in Flagler County when soil has warmed and frost danger has passed.

Sandy soil in Flagler County dries quickly — mulch Hyssop with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

With summer highs reaching 99°F in Flagler County, provide afternoon shade for Hyssop and water deeply in the morning.

General growing tips

Start seeds indoors or direct sow in spring. Prune back in early spring to encourage bushy growth. Hyssop is drought-tolerant once established and thrives in poor soil.

Companion Planting

Good Companions

Avoid Planting Near

  • Radish

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hyssop in Flagler County, FL?

Flagler County is in Zone 9b with an average last frost of February 5. Plan your Hyssop planting based on this frost date — see the calendar above for exact timing.

What planting zone is Flagler County, FL?

Flagler County, Florida is in USDA Hardiness Zone 9b. The average last spring frost is February 5 and first fall frost is December 17.

🌱

Your Flagler County Garden Planner — Free

A 24-page printable planner built for Flagler County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Flagler County, FL. Local conditions may vary. Last updated: May 2026.

Sources & credits

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